Swole Ignition coils, blowing fuse and big problems on my Jazz

[Dwight]

Yes, I hope there's not something deeper behind all those issues indeed... We'll see.

I suggest you take a look at your ignition coils when you can, since it's easily accessible and inspectable just by removing the top engine cover and its two bolts...

Just to give anyone an idea, I'll attach pictures with the "badest" looking ones that I pulled from my Jazz.

Cheers

[Dwight]

Well folks... Guess it was a very very short victory.

Earlier today while I stopped the car to get a phone call, it started idling weird, engine light flashing... Turned the car off, checked the fuse, F24 was out again...

Put a new one, and I guess it blew immediately since it kept running bad till I got home, a few kilometers away. When I got home, checked both our guilty fuses, and while N°2 was still ok (which probably helped me limp back home) n°24 was out again...

So here we are, back to the beginning I guess 

[CRC]

Time to look at the graphic I added to post #12 I reckon.

To take a 15 amp fuse out, it must be shorting out to ground somewhere in the circuit.

Fuses can just fail through age, but if they keep blowing, it tells you that a big current is flowing through that fuse at certain times, and as it's now happened with 2 sets of coil packs, the wiring is the next thing to have a look at imho

[CRC]

There's one other thing that wiring diagram shows connected to one of the fused lines, a wire leading to something called an OPDS module.
The only thing I can find on this that it's possibly a Occupant Position Detection System module and it seems to be located around the rear seats area.
I don't know what it's used for, how it works or why it would be wired into the fuse that feeds the coil packs on the engine ..... or even if the wiring diagram is exactly right???
Clear as mud, really.....

[Dwight]

Hey,

So I tinkered a bit this afternoon, and tried to see if I could investigate more about this issue.

First thing I inspected are the two grounds I know, which are the one directly on the battery, connected to the body (see first attachment), looking alright to me, and the one under the battery tray, attached from the engine mount to the body, looking a bit off so I'll clean it anyway (see second attachment).

But honnestly, I struggle to believe it would be a short or bad ground on those two "general" grounds that would cause our issue, since I'm pretty sure it wouldn't just create problems on ignition coils, but to other eletrical components on the car too, which isn't the case so far...

Other important thing, I then managed to find out with a multimeter to which fuse each bank of coils matches. So fuse n°2 is for the rear bank of ignition coils, and fuse n°24, the one that keeps on blowing first, is for the coils on the bank on the front of the engine.

I then saw that the harness looked different on the front than on the back, and that the end of the front harness, the end meaning the plug on the very front left ignition coil, was with some kind of white sleeve, instead of the black plastic kind of deal (see attachment 3).

Hopeful it was the sign of someone who maybe had done some fixing on the wire harness before, I decided to take off the airbox, and the whole intake assembly to have some clear view of that harness, and to open it carefuly, see if anything wrong is obvious, like a barely hanging wire or something. You can see on the last attachment I opened it up to the side of the engine (blue circle) and so far found nothing out of the ordinary, nothing cut. That was kinda of disappointing to be honnest, especially when I know I'll have to redo the sleeve arround everything I removed, basically for nothing for now. Lol. That's the game.

So I don't know what to do next, I'm considering on keeping on pushing on the coils harness and see if it brings to something?

What do you guys think honnestly?

Also, I was wondering, eventhough my spark plugs are only 3 years old, could they be wrong? Could one be bad and cause this mess?

I remember taking some good plugs, like NGK or Bosch, but still.

[CRC]

Don't despair, you're doing the right things and you're looking in the right place.

Don't worry about the spark plugs, you're looking for a fault in the 12 volt  feed to the coil packs, not the high voltage side of the coil packs.

Well done for identifying that the most problematic fuse 24 feeds the front bank of coils, and the fact that someone has obviously been into that area before is telling you that there was possibly an issue there before and that someone must have had a good reason to strip it back looking for the problem.

The photos show a black core with a yellow stripe and the wiring diagram shows that these cores are connected to the fused side of F24.

Remove that fuse and take your multimeter set to ohms, put the black probe onto a good ground point or the negative post of the battery, put the red probe into each of the coil pack plugs where the black / yellow core comes in.

If the core is good and insulated, you should see "open circuit" on the multimeter, as there should be no connection at all to ground.  Wiggle the wires, bend them, look for anything that might show an ohms reading as the core inner finds a route to earth.

Somewhere along the line, those 4 black and yellow cores have to join a single core that goes back to the fuse and it would be good if you could find that.

If you can't find anything, put a new fuse into F24 and look for 12v being present on the black / yellow core at each of the coil plugs. Wiggle the wires as much as possible and see if you can make the fuse blow. If you can, then you know that there's an issue in the wiring somewhere.

Always suspect areas with electricians tape wrapped round them .... there are a lot of cowboys out there ...

[CRC]

The second coil from the left on picture 4 - looks like a wrap of yellow electrician's tape above a wrap of black electricians tape?

I'd definitely be looking to see what's under those because I can't imagine that tape was put on at the factory....

[Dwight]

Thank you for your support and advices.

I will try what you suggested tomorrow if possible with the help of my neighbour, he's a former electrical engine builder and definitely knows much more about electricity overall than I do. He is the one who helped me figure out which fuse goes to which bank.

And about that yellow tape, it's a small piece over a green wire going to one of the injector plug, I kind of slightly damaged the coating when cutting the harness open, I put it there to remind myself to fix it before I redo the harness :'(

[CRC]

Good luck.

At the end of the day, you've got 4 brand new coil packs eventually connected to a single core that comes from a single fuse.

You know the coil packs are ok because the car has happily run for probably tens of thousands of cycles.

If the coil packs are good, then the only thing it can be is the wiring touching something else intermittently, causing a brief current greater than the fuse rating.

[jaxabin]

was it difficult to take off the intake manifold? I’m going to do it soon to try and fix my EGR insufficient flow problem

[Dwight]

No it's fairly easy to take it off. I suggest removing the airbox, then unbolting the throttle body from the intake. Then you've got 3 bolts on the front of the intake holding some harness that you can remove.

The intake itself is held by 3 12mm bolts on the very bottom of it (when you look down over your engine basically), one on  far left near alternator, one center and one far right near the two black metal pipes.

You then have two 12mm nuts in the same area but a bit higher, kind of hidden, squeezed between the intake "trumps" (idk if that's how you call the four of them, but you can picture it).

Then you have one bolt on the top of the engine, behind the intake on its right corner holding a little metal plate which itself holds with two nuts the mounting for the throttle body on the intake. You'll see what I'm talking about by peeking at it.

Then basically you're done. Takes about 10-15 minutes top. Good luck.

I'm going to keep on investigate now, I have some time on my hand and it's a beautiful sunny day. I'll report if I find anything.

By the way, just a thought, but what about the fusebox itself, could it be bad? I have some humidity problem in the car, when it's cold and humid, I always find the inside of the windshield completely wet.

I'd assume this water must go somewhere, and if when I see it, I dry it with the heater, when I don't see it,  like when the car is parked for a few days, maybe that water has to go somewhere, and maybe it tends to slide down the inner windshield and slither behind the dashboard and could damage or get some components rusting, like the fusebox...?

I don't know, I just might be overthinking here. See you guys later.

[CRC]

Water ingress and electrics don't sit well together, with the worst culprits being the manufacturers that fit electronic control modules in the well underneath passenger and driver seats. Any water ingress into the cabin through door seals, window seals, pollen filter seals etc always eventually finds the lowest point in the car and drowns the electronic modules, with a very expensive repair inevitable.

Electronic boards hate getting wet and green copper corrosion on the edge connectors causes all sorts of issues.

However, the fuse box on the Jazz is mounted vertically just down from the dash from memory, and it's purely separating a large 12 volt feed into multiple smaller feeds, so far less likely to suffer.

Having said that, have a feel around see if you can detect any moisture . Safety point, don't wear an sort of ring when you're fishing around behind the dash as they're not much fun if they short something out ......

Could well be worth pulling any multicore connectors on the front of the fuse board, squirting with contact cleaner and plugging them in again.

A fuse blows when the current flowing through the tiny fuse strand is greater than it can flow without glowing red hot and burning out and this normally only happens when metal to metal contact causes a large flow of current (amps).

In general, the fuse rating is to protect the wiring, not the item itself.

Many years ago, we had a mini van that somehow lost it's earth strap connection to the engine and the starter motor current decided to use the throttle cable as it's return path to the battery. Smoke, melted plastic, nightmare ...

[Dwight]

Alright, so not much advancement sadly.

I managed to open the harness sleeve even more to track down the wires, and remove a bunch of things on the way. Just putting everything back together and redoing the harness clean will take at least 2 hours, and it was all for nothing much for now, lol.

So basically, I managed to find out that all the ground wires for eight ignition coils were merging (attachment 1) into 2 black wires connected to a ground (attachment 2).

Same things goes for all the black/yellow wires being the positive I'd assume, are going into some kind of big square plastic junction block (attachment 3) and the four blk/yel wires of front bank of coils merge into one single black/white striple wire, and the four blk/yel wires of the back bank of coil merge into one single black/yellow (the same basically) wire.

Those two new wires go into some kind of grey plug behind the battery tray (see attachment 4) and it seems that the wire would then go up and go along the body of the car, in the corner and up... I didn't follow more after that.

Tried continuity of all front bank positive wire until that grey plug, was good.

Also tried the think with disconnecting the fuse and search for continuity when there shouldn't be, while janking the harness. Nothing jumped out.

So for now, I'm having second thought about the whole harness theory. Sure it makes sense in the way basically a fuse blows out, so there's a surge. But the very fact the harness doesn't move at all, was well attached everywhere, nor looking weird anywhere (even the white sleeve I was finding weird compared to the rest, turns out it must be stock since there's the same kind on the alternator wire), so overall it's not a janky wiring harness, it's solid, doesn't move much.

What bothers me much in that whole theory too is the fact if there was something in that very "static" harness, it would blow up immediately, each time I turn the key on or start the engine.

And for some reason, when I changed both F2 and F24 fuses the other day, I managed to use the car without troubles for the whole rest of the day and the morning after, granted I didn't run 100km, but still, I did about 20 km and mainly bumpy city roads, corners, anything that could make the harness or a wire or connection move, but nothing blew while running. It blew when I was parked and idling. 

But for some reason, and again, fuse 24 blew when I stopped the car to take a phone call, so engine at idle again, like the very first time when everything started on that parking... Coincidence?

Weirdly enough, seems like once the problem does appear and F24 blows, putting a new one immediately after doesn't solve the issue this time, and it blows too almost immediately when starting the car... Excuse my language but WTF?

So could there be something to dig arround that "parked and running at idle" car coincidence?

Also, couldn't it be something with the timing being off? Would a bad timing possibly manage to blow the fuse out of security?

And if so, could it be linked to the TDC sensor, or ECU being toasted?

Just throwing theories there, don't mind me. My knowledge on electricity overall are close to none, and while some thing make sense and are logical to me, some aren't and I'm trying to make a sense out of it all.

[CRC]

You're doing really well by refusing to let it beat you, and none of this effort is ever wasted, as at least you now know "what it's not" and also you've learnt a lot about electrics, multimeters etc.

What to do next.....?

The first thing I would while you're in there is loosen that ground that the black wires connect to. If it turns easily and comes out easily, clean it all up with a wire brush and put it back together.

Ricky Elder (RETuning, YouTube) was diagnosing a misbehaving R8 in his latest video and he wouldn't even start trying to faultfind until he'd spent an hour or so cleaning up the earth connection as it can cause a lot of weird issues.

Assuming that's ok, this is now a proper puzzle, as it's hard to work out what can be causing that big current, as the wiring has now been tested out.

Each coil pack has a wire direct from the ECU to cause the spark to happen at the right instant, but they must be ok as the system works fine for long periods.

It's very hard to see what can cause a fuse to blow when the only things connected to it are new coil packs which have been tested ok. What make are the coil packs out of interest?

I can't really see how tickover can change anything related to that harness and the coil packs  .... will start hunting around for some clues and get back to you if I find anything.

[Dwight]

Thanks for your answer

Yes, like you I assume coil packs are good, because they're new, but to be honnest, I bought them on Amazon for like 90€ the set of 8. The brand is called "Germban", probably to make it sound german when I'm about 90% sure it's some "Made in China" and that you can find the same on Aliexpress for like 30€.

However reviews were good about it, and since this whole issue really strikes when in a moment where I'm very short on coins, I decided I would go for them and would invest in some better brand, Bosch, Hitachi or alike in a couple years when finances allow me to.

So yea, seriously what would be the odds that:

1.Old coils are bad and overheated and die on me while idling, making fuses blow
2.I put new coils but they're cheap and made in china so they're now the one causing the same issue with the same symptons and blowing fuses

No seriously, I'm really out of ideas now. I don't really know where to look, beside maybe keeping on following those two main positive wires after the grey plug...